Silencer



United States Patent O U.S. Cl. 55--276 6 Claims ABSTRACT F THE DISCLOSURE A baffling means for a solid particle eliminating -gas flow device, such as a spark arresting muliler, includmg gas rotating means mounted near the inlet thereof, solid particle trapping means and an outlet tube for expelling the rotating, relatively solid particle-free gases therefrom. The baffling means comprises a flat or planar plate member mounted within the outlet tube a predetermined distance from the inner end and along the central axis thereof. The length of the plate member may vary. The plate member serves to eliminate whistling sounds caused by the passage of the rotating gases over the inner edge of the outlet tube.

BACKGROUND OF THE INVENTION This invention relates generally to engine inlet and exhaust silencers and mufflers or the like devices and has particular reference to mulers of the spark arresting type.

Devices of the foregoing type are designed to trap sparks or incandescent solid particles or other solid particles in the exhaust or inlet gas stream by causing the gases coming into the device to swirl or spin by means of built-in louvers or the like. As the gases spin, the heavier, solid particles are, by centrifugal force, thrown to the outer wall of the muler and are trapped in a chamber provided thereat. The lighter gases, hot trapped in the side chamber, pass through the central outlet tube of the muffler relatively free from solid particles. In a like manner, solid particles may be removed from the inlet air supply to a carburetor.

As a result of the inward flow of the spinning exhaust gases ory air, as the case Imay be, it is common to develop a whistling sound as the gases flow across the inner end of the outlet tube of the spark eliminating portion of the muffler, etc.

A suggested technique in reducing or eliminating this objectionable whistling sound, has been to flare the inner end of the outlet tube. Such flaring, however, is not a satisfactory solution to the whistling action and, in fact, makes the assembly of the muiiler more difficult and costly, since the diameter of the tube at the ared end is larger than the hole in the body of the muffler, and therefore must be inserted from the opposite end thereof.

SUMMARY OF THE INVENTION Accordingly, it is a general object of this invention to provide a new and improved solid particle eliminating gas flow device, such as, for example, a muffler, in which a whistling sound caused by gases passing over the inner edge of the outlet tube thereof is substantially reduced or eliminated.

It is another object of this invention to provide a muffler or the like device of the type mentioned above, which is easily assembled and relatively inexpensive to produce.

It is a more specific object of this invention to provide baffling means for use in a mufer or gas flow device of the spark arresting or solid particle eliminating type, wherein a whistling sound produced by swirling gases flowing therethrough is made inaudible to the human ear.

3,545,179 Patented Dec. 8, 1970 DESCRIPTION OF THE DRAWING A better understandin-g of the present invention and its organization and construction may be had by referring to the description below in conjunction with the accompanying drawings, wherein:

FIG. 1 is a longitudinal section view of one embodiment of a gas ilow device of the solid particle eliminating or spark arresting type, employing a baliiing means according to the invention;

FIG. 2 is a longitudinal sectional view of a second embodiment of a gas ilow device of the above mentioned type, also employing a bathing means according to the invention;

FIG. 3 is a cross-sectional view of the device of FIG. 1 taken along the line 3-3 thereof;

FIG. 4 is a cross-sectional View of the device of FIG. 2, taken along the line 4-4 thereof; and

FIG. 5 is a cross-sectional view of the device of FIG. l, taken along the line 5 5 thereof.

DETAILED DESCRIPTION Referring now to the drawings in greater detail, FIG. 1 thereof shows a lirst embodiment 10 of a gas flow device or muflier of the solid particle eliminating or spark arresting type. The muier includes an lelongated cylindrical or tubular shaped outer housing 12 having an inlet end 14 and an outlet end 16. An inlet tube 18 is mounted by means of a pair of circular shaped support plates 21 and 22 welded to housing 12 at the inlet end 14 thereof; plate 21 also serving as one end wall of the housing. An outlet tube 20 having holes 22 is mounted by means of a circular end wall 24 Welded to the tubular housing 12 at the outlet end of the muiller. Secured to the wall of the housing 12 adjacent the inner end 26 of the inlet tube 18 and in spaced apart relation therewith, is a circular, gas swirling or rotating disc 28, shown in greater detail in FIG. 3. As can be seen in FIGS. 1 and 3, the disc 28 includes a plurality of orifices 30` and associated air directing anges 32, here shown for directing the gases in a clockwise rotation as they pass therethrough (FIG. 3). Adjacent disc 28, toward the outlet end 16 of the muffler, there is provided a solid particle trap assembly 34. The trap assembly includes an outer chamber 36 which is located between the outer housing 12 and an inner wall 38 of the assembly 34, and an inner chamber 401 into which the inner end 42 of the outlet tube 20 extends, as shown in FIG. l. The end 42 of the outlet tube 20 is supported in the solid particle eliminating assembly 34 by means of circular support members 44 and 46 spot-welded to the outlet side of the assembly 34. The support member 44 serves also to seal the outlet tube 20 in the assembly 34 allowing passage of gases only through the outlet .tube itself.

The operation of the solid particle eliminating muffler device 10 of FIG. 1 is as follows: exhaust or inlet gases, comprising a mixture of gas and entrained solid partlcles, enter an end 52 of inlet tube 18. The gases pass through the tube and encounter disc 28. The gas flow indicate by the arrows, proceeds through the orifices 30 and the gases are caused to be swirled, in this case, in a clockwise rotating manner. Having passed through disc 28, the swirling gases flow into the solid particles eliminating assembly 34. The centrifugal force of the swirlmg gas ow causes the larger solid particles to be thrown to the outside thereof and as they pass through the assembly 34, are caused to flow about, but not into, the inner end 42 of the outlet tube 20. After the larger solid particles have flowed past the inner end 42 of the outlet tube 20 they are driven through a series of louvers 54 into the chamber 36, and are trapped in the chamber. The relatively solid particle free gas ow (Le. gases containing only smaller particles if any) continues into the inner end 42 of outlet tube 20 and out the outer end 50 into the atmosphere, or into the engine as the case may be.

The solid particles which are meant to be trapped in chamber 36 in the case of a mulher 10 are those which in an inlet would damage the engine or in an exhaust are glowing and hot, and which, if passed through the muffler and ejected into the atmosphere could cause hres if they fell into dry grass, etc. on the earth. The particles may be released periodically from the chamber through the plugged aperture 62 at the lower end of the chamber (FIG. 1).

The action of the rotating, relatively solid particle free gases passing over the edge 56 of the inner end of the outlet tube causes a whistling sound which can be disturbing to the ear. To eliminate this whistling sound, a bathing means 58 is provided in the outlet tube 20. The bathing means as shown herein comprises a flat or planar plate 60 located within the outlet tube and extending diametrically in relation thereto. The plane of the plate is mounted along the central axis of the tub'e and, as will be noted in FIG. l, the leading edge 61 of the plate is positioned a short distance from the inner edge 56 thereof. The minimum practical length Y of the plate 60 is one inch, however, a preferable length is subtsantially as long as the outlet tube in which it is located. This provides (as shown in FIG. 1) for the accommodation of a wider range of gas tlow velocities. It has been found that a bathing plate one to two inches shorter than the outlet tube length permits ready access by a welding torch or other suitable fastening means, so as to easily assemble the bathing plate within the outlet tube.

The bathing means 58 serves to eliminate or reduce the swirling or rotational action of the relatively solid particle-free gas how as it passes over the inner edge of the tube 20. The rotating gas how entering tube is straightened by the bathing plate 60, and a back pressure is thereby caused in the tube to reduce or eliminate the whistling sound. The correct placement of the leading edge 61 of the plate a short distance from the inner edge 56 of the tube causes the back pressure produced to be etfective at the inner edge 56 of the tube and thereby straightens the rotating gas how before passing over the inner end of tube 20.

The use of the bathing means 58 according to the invention is not limited to a muther or gas ow device of the type shown in FIG. l. It may tind use in practically all gas flow devices of this type. In addition, the outlet tube need not be a direct discharge tube, but may serve only as an outlet tube from the particle eliminating chamber into another chamber where further acoustical treatment of the gases is provided prior to discharge.

A second muther or gas how device 70 is illustrated in FIG. 2 of the drawings. This device 70 is similar to the one of FIG. 1, in that it includes a cylindrically shaped outer housing 72 having an inlet end 74 and an outlet end 76. An inlet tube 78 is mounted by means of a circular end wall 80 at the inlet end 74 of the device 70. Rather than containing a separate disc such as 28 in FIG. 1, for rotating the gases as they leave the inlet tube, the inlet tube 78 itself is constructed so as to swirl or rotate the gases entering therein. This is accomplished by providing, along the outer wall 82 of the inlet tube 78, on a portion thereof within the housing 72, a series of louvers 84. To see these louvers 84 in greater detail, attention is drawn to FIG. 4 of the drawings. In FIG. 4 it can be seen that the louvers 84 are cut from the wall 82 of the inlet tube 78 and are bent outwardly therefrom in a common direction; shown in FIG. 4 to be opening in a clockwise direction. Thus, gases entering the inlet tube 78 are swirled outwardly from the apertures 86.

In any event, the gases, whether by using a disc similar to 28 or the louvered inlet tube 78, are spun or rotated as they enter the solid particle trap assembly 88, as shown in FIG. 2. The trap assembly 88 is like that of FIG. 1 and thus will not be described in detail.

Just as in the case of the gas flow device of FIG. l, an outlet tube 90 is provided at the outlet end 76 of the outer housing 72. The outlet tube 90' is supported by means of the opposite end wall 92 of the housing. The inner end 94 of the outlet tube is inserted into the trap assembly 88 and is supported thereat by a circular support plate 96 welded to the trap assembly and inner wall of the housing. The outlet tube 90 ditfers from the outlet tube 20 of FIG. 1, in that it is of greater length and contains a plurality of apertures such as 98 extending through the outer wall 100 thereof. The apertures tend to allow a portion of the gas entering the outlet tube to pass therethrough into and then return from the space or cavity 102 between the outer housing 72 and the outlet tube 90. This causes a breaking-up of the gases prior to exiting from the outlet tube, and reduces the noise level.

I ust as in the case of the device of FIG. l, gases entering the inner end 94 of outlet tube 90 are rotated, and as they travel over the edge 104 of the outlet tube 90, would tend to cause a whistling sound. To eliminate this sound a bathing means 58 has been provided in the outlet tube 90. The bathing means 58, as shown in FIG. 2, comprises a plate member 106 which is mounted within the tube 90 a distance A from the edge 104 of the inner end 94 thereof. The plate is welded at both ends thereof to the tube and extends along the diameter thereof. The length B of plate member 106 is less than the plate length Y of FIG. l, but nevertheless serves to eliminate sounds caused by the action of the gas tlow over the inner edge 104 of tube 90. Also provided in and seA cured to the outlet tube 90 is an apertured disc 108 for further breaking up the gases as they how through the tube 90 prior to their being expelled therefrom at end 110 thereof.

While particular embodiments of the bathing means according to the invention have been shown and described, it should be understood, of course, that the invention is not limited thereto, since many modifications thereof may be made. It is therefore contemplated to cover by the present application any and all such modifications as fall within the true spirit and scope of the appended claims.

What is claimed is:

1. A gas how device comprising a housing having an inlet end and an outlet end; an inlet tube mounted at the said inlet end and extending into said housing and including about the wall thereof within the housing a plurality of louvers for rotating gases entering said inlet tube; means located within said housing and following the louvered end of said inlet tube for trapping solid particles removed from the rotating gases and including a cylindrical wall spaced within said housing by forward and rearward annular wall support means secured to the housing to provide an annular solid particle trapping chamber with particle ingress thereto through apertures in said cylindrical wall adjacent the rearward wall support means and with particle egress therefrom through a discharge aperture in the housing; a multi-apertured cylindrical outlet tube for expelling gases relatively free of solid particles from said housing and traversing the housing from the outlet end thereof to within said cylindrical wall and supported by said rearward wall support means Which defines with the outlet end of the housing an expansion chamber around the included length of the outlet tube; a bathe plate member for reducing noise of rotating gases passing across the inner end of the outl'et tube and having a width substantially equal to the diameter of the outlet tube and mounted therein with the inner edge thereof parallel to the diameter of the outlet tube and spaced inwardly of the inner end of the outlet tube, and said bathe plate member extending toward the opposite end of the outlet tube substantially along the axis thereof; and an apertured disc traversing the outlet tube between the edge of the bathe plate member and the outer end of the outlet tube for further breaking up the flow of gases flowing along the outlet tube toward the outer end thereof.

y2. A gas ow device as claimed in claim 1, wherein the said cylindrical wall provides an expansion chamber in advance of the rear-ward wall support means around the inner end of the outlet tube.

3. A gas ow device comprising a housing having an inlet end and an outlet end; an inlet tube mounted at the said inlet end of the housing; a multi-apertured outlet tube mounted at the outlet end of said housing and traversing a substantial portion of the length thereof with the inner end thereof spaced from the inner end of the inlet tube; means located within the housing and following the inner end of the inlet tube for trapping solid particles and including a cylindrical wall spaced within the housing by forward and rearward annular wall support means secured to the housing to provde with said housing an annular solid particle trapping chamber with particle ingress thereto through peripherally disposed inlet apertures in said cylindrical wall adjacent the rearward wall support means; said rearward wall support means also supporting the adjacent inner end portion of the outlet tube; said outlet tube dening with the outlet end of the housing an expansion chamber around the included length of the outlet tube; a discharge aperture in the housing iluidly communicating said trapping chamber with the exterior of said housing and providing particle egress from said housing and said trapping chamber; means in advance of said trapping chamber for rotating the gases in said housing and causing solid particles to be thrown outwardly along said cylindrical wall and enter said trapping chamber through said inlet apertures; and a bale plate member for reducing noise of rotating gases passing across the inner end of the outlet tube and having a width substantially equal to the diameter of the outlet tube and mounted therein with the inner edge thereof parallel to the diameter of the outlet tube and spaced inwardly of the inner end of the outlet tube, and said baffle plate member extending at least partially toward the opposite end of the outlet tube substantially along the axis thereof.

4. A gas ow device as claimed in claim 3, wherein the rotating means for the gases comprises a disc member spaced between the inner end of the inlet tube and the adjacent end of the trapping chamber and having radially outwardly extending cut-outs for rotating the incoming gases passing therethorugh from the inlet tube.

v5. A gas flow device as claimed in claim 4, wherein the bafe plate member is substantially coextensive in length with the expansion chamber around the outlet tube.

6. A gas flow device as claimed in claim 3, wherein the baille plate member is substantially coextensive in length with the expansion chamber around the outlet tube.

References Cited UNITED STATES PATENTS 223,403 l/ 1880 Stewart -455X 887,893 5/1908 Wickstrum 55-396 1,899,911 2/1933 Kamrath 55-276UX 2,322,414 6/1943 Bowen 55-396 2,329,101 9/ 1943 Chipley 181-58X 2,511,190 6/1950 Wright 18l--58X 2,560,077 7/1951 Bloomer et al. 55--455X 2,730,193 1/1956 Hoyle 55-395 3,239,317 3/1966 Rhodes 23-288(.3F)

FOREIGN PATENTS 1,059,584 11/1953 France 181-58 DENNIS E. TALBERT, JR., Primary Examiner U.S. Cl. X.R. 

